          (color? absorb) (optional color? absorb-hsb)
          (number? abs-scale) (number? abs-depth)]}
   (append
-   scene :volumes (name id)
+   scene :volumes id
    {:__type type
     :fresnel [:float (if (keyword ior) (presets/ior-presets ior) ior)]
     :absorption [:log-color [(if absorb-hsb (col/hsb->rgb absorb-hsb) absorb)

  [scene id alpha]
  (if (< alpha 1.0)
    (material-mix
     scene (name id) "__hidden__" (material-id id alpha) alpha)
    scene))

(defn material-matte

             :or {cone-angle 30 cone-delta 5 from [0 0 1] to [0 0 0]}
             :as opts}]
  (append
   scene :lights id
   (merge
    (light-common scene opts)
    {:__transform tx
     :__type :spot-light
     :from [:point-vec [from]]
     :to [:point-vec [to]]
     :coneangle [:float (->degrees cone-angle)]
